JP7094852B2 - Image sensor and image sensor - Google Patents

Description

The present invention relates to an image pickup device and an image pickup apparatus.

Conventionally, as an AD converter for converting a signal from a CMOS image sensor or the like into a digital signal, an image pickup device including a plurality of AD converters using a lamp waveform is known (see, for example, Patent Document 1).
Patent Document 1 Japanese Patent Application Laid-Open No. 2006-303752

Since a common lamp waveform is input to a plurality of AD converters, it is difficult to independently adjust characteristics such as gain in each AD converter.

In the first aspect of the present invention, there is a first image pickup region and a second image pickup region, and the first image signal generated in response to the light incident on the first image pickup region and the second image pickup region are incident on the first image signal. An image pickup unit that outputs a second image signal generated in response to light, a first lamp generation unit that generates a first lamp signal, a second lamp generation unit that generates a second lamp signal, and a first image. Based on the comparison result between the signal and the first lamp signal, the first signal conversion unit that converts the first image signal into the first digital image signal, and the comparison result between the second image signal and the second lamp signal. Provided is an image pickup element including a second signal conversion unit that converts a second image signal into a second digital image signal.

In the second aspect of the present invention, an image pickup device provided with the image pickup device of the first aspect is provided.

The outline of the above invention does not list all the features of the present invention. A subcombination of these feature groups can also be an invention.

It is a figure which shows an example of the structure of the image pickup device 100 which concerns on embodiment of this invention. It is a figure which shows the structural example of the image pickup region 131 and the AD conversion unit 180. It is a timing chart which shows the operation example of the 1st imaging region 131-1 and the 2nd imaging region 131-2. It is a figure which shows the example of a plurality of image pickup regions 131. It is a figure which shows the other example of a plurality of imaging regions 131. It is a figure which shows the other example of a plurality of imaging regions 131. It is a figure which shows the structural example of the image pickup unit 120 and a plurality of AD conversion units 180. It is a timing chart which shows the operation example of four AD conversion units 180 provided in the same column. It is a timing chart which shows the detail of the operation of the 1st AD conversion unit 180-1 and the 2nd AD conversion unit 180-2 in the operation example shown in FIG. It is a timing chart which shows the other operation example of four AD conversion units 180 provided in the same column. It is a timing chart which shows the detail of the operation of the 1st AD conversion unit 180-1 and the 3rd AD conversion unit 180-3 in the operation example shown in FIG. It is a figure which shows the image of the read timing difference in rolling read. It is a figure which shows the structural example of a plurality of lamp generation part 182. It is a figure which shows the other structural example of a plurality of lamp generation part 182. It is sectional drawing of the image pickup device 100 which concerns on this embodiment. It is a block diagram which shows the structural example of the image pickup apparatus 500 which concerns on Example.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention to which the claims are made. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

FIG. 1 is a diagram showing an example of the configuration of the image pickup device 100 according to the embodiment of the present invention. The image sensor 100 is, for example, a camera that captures a still image or a moving image. The image pickup device 100 of this example includes an image pickup unit 120, a plurality of AD conversion units 180, and a plurality of lamp generation units 182.

The imaging unit 120 has a plurality of imaging regions 131. Each imaging region 131 accumulates an electric charge according to the incident light. Each imaging region 131 has one or more photoelectric conversion units that convert incident light into electric charges and store them. The image sensor 100 generates an image signal according to the incident light by reading out the amount of electric charge accumulated in each image pickup region 131. FIG. 1 shows a first image pickup region 131-1 that generates a first image signal and a second image pickup region 131-2 that generates a second image signal.

The first imaging region 131-1 has one or more first photoelectric conversion units, and the second imaging region 131-2 has one or more second photoelectric conversion units. For example, the imaging unit 120 has a plurality of photoelectric conversion units arranged in a matrix, and each imaging region 131 may include one row of photoelectric conversion units. Further, the imaging region 131 may include photoelectric conversion units arranged separately. Further, the imaging region 131 may be a block having a predetermined length (number of photoelectric conversion units) in the row direction and the column direction.

The AD conversion unit 180 is provided corresponding to each imaging region 131. FIG. 1 shows a first AD conversion unit 180-1 and a second AD conversion unit 180-2 corresponding to the first imaging region 131-1 and the second imaging region 131-2. Each AD conversion unit 180 is an example of a signal conversion unit that converts an analog image signal according to the amount of charge storage in the corresponding image pickup region 131 into a digital image signal. The first AD conversion unit 180-1 converts the first image signal into a first digital image signal, and the second AD conversion unit 180-2 converts the second image signal into a second digital image signal. When the imaging region 131 includes a plurality of photoelectric conversion units, the AD conversion unit 180 may sequentially read out the charge amounts generated by the plurality of photoelectric conversion units and convert them into digital image signals.

At least two lamp generation units 182 are provided. FIG. 1 shows a first lamp generation unit 182-1 and a second lamp generation unit 182-2 provided corresponding to the first AD conversion unit 180-1 and the second AD conversion unit 180-2. Each lamp generation unit 182 generates a lamp signal. Characteristics such as the inclination of the lamp signal generated by each lamp generation unit 182 can be independently controlled for each lamp generation unit 182. The lamp generation unit 182 may be provided in a one-to-one correspondence with a plurality of AD conversion units 180, and at least a part of the lamp generation units 182 may be shared by two or more AD conversion units 180.

Each AD conversion unit 180 converts an image signal into a digital signal based on a comparison result between the lamp signal generated by the corresponding lamp generation unit 182 and the corresponding image signal. For example, the AD conversion unit 180 outputs a digital value according to the time from the timing when the lamp signal is received to the timing when the level of the lamp signal and the level of the image signal intersect, thereby setting the level of the image signal to a digital value. Convert to.

Since the image pickup device 100 of this example includes a plurality of lamp generation units 182, lamp signals having different characteristics can be used for each image pickup region 131. For example, by using lamp signals having different inclinations with respect to the first imaging region 131-1 and the second imaging region 131-2, the digital value of the digital image signal with respect to the analog level of the image signal output by the imaging region 131 The gain can be different. Further, by using the lamp signals generated at different timings for the first image pickup area 131-1 and the second image pickup area 131-2, it is possible to make the read timing of the image signal output by the image pickup area 131 different. can.

FIG. 2 is a diagram showing a configuration example of the imaging region 131 and the AD conversion unit 180. In this example, the image pickup unit 120 including the plurality of image pickup areas 131 is provided on the image pickup chip 113. Further, the plurality of AD conversion units 180 and the plurality of lamp generation units 182 are provided on the signal processing chip 111. FIG. 2 shows a set of imaging regions 131, an AD conversion unit 180, and a plurality of lamp generation units 182.

The image pickup chip 113 and the signal processing chip 111 are, for example, semiconductor chips. The signal processing chip 111 is laminated with the image pickup chip 113. For example, the signal processing chip 111 is arranged so as to overlap the image pickup chip 113, and is electrically connected to the image pickup chip 113 via a bump 109 or the like. As described above, by providing the image pickup unit 120, the AD conversion unit 180, and the lamp generation unit 182 on different chips, the plurality of AD conversion units 180 and the plurality of lamps are suppressed while suppressing the increase in the area of the image pickup unit 120. The generation unit 182 can be easily provided. Further, the wiring length between each photoelectric conversion unit 104 and AD conversion unit 180 can be shortened, and the image signal can be read out with high accuracy.

The imaging region 131 includes one photoelectric conversion unit 104, a transfer transistor 152, a reset transistor 154, an amplification transistor 156, and a selection transistor 158. The source and drain of the transfer transistor 152 are connected to the output end of the photoelectric conversion unit 104 and the gate of the amplification transistor 156, respectively. The parasitic capacitance in the wiring between the output end of the photoelectric conversion unit 104 and the source of the transfer transistor 152 functions as a charge storage unit that stores the generated charge of the photoelectric conversion unit 104. In this example, the charge storage unit is a part of the photoelectric conversion unit 104. A transfer signal Tx that controls whether or not to transfer the accumulated charge amount by the charge storage unit is input to the gate of the transfer transistor 152.

A reference voltage VDD is input to the drain of the reset transistor 154, and the source is connected to the gate of the amplification transistor 156. A reset signal Reset that controls whether or not the charge amount accumulated by the charge storage unit is reset is input to the gate of the reset transistor 154.

A reference voltage VDD is input to the drain of the amplification transistor 156, and the source is connected to the drain of the selection transistor 158. The amplification transistor 156 outputs an analog image signal according to the amount of electric charge transferred from the transfer transistor 152. A selection signal Select is input to the gate of the selection transistor 158, and the source is connected to the AD conversion unit 180. The selection transistor 158 inputs the image signal from the transfer transistor 152 to the AD conversion unit 180 according to the selection signal Select.

In the example of FIG. 2, the imaging region 131 having one photoelectric conversion unit 104 is shown, but a plurality of photoelectric conversion units 104 may be provided in the imaging region 131. When a plurality of photoelectric conversion units 104 are provided in the imaging region 131, the corresponding AD conversion units 180 sequentially read analog signals according to the charges accumulated by the respective photoelectric conversion units 104.

The AD conversion unit 180 includes a level comparator 184 and a period measurement unit 186. The level comparator 184 compares the level of the lamp signal input from the corresponding lamp generation unit 182 with the level of the image signal from the corresponding imaging region 131. For example, the level comparator 184 outputs a logic value 0 when the level of the image signal is smaller than the level of the lamp signal, and outputs a logic value 1 when the level of the image signal is equal to or higher than the level of the lamp signal.

The period measuring unit 186 measures the period from the timing when the lamp generation unit 182 starts inputting the lamp signal to the level comparator 184 to the time when the level comparator 184 outputs the logical value 1. The period measuring unit 186 may be a counter that receives a clock signal having a predetermined frequency and counts the number of pulses of the clock signal within the period. The period measurement unit 186 outputs a digital value according to the length of the measured period. As an example, the period measurement unit 186 outputs the number of pulses of the clock signal counted within the period as a digital value.

According to the AD conversion unit 180 of this example, the level comparator 184 outputs a logical value 1 from the timing when the lamp generation unit 182 starts inputting the lamp signal to the level comparator 184 according to the inclination of the lamp signal. The period until it is changed. Therefore, the gain in the AD conversion unit 180 can be controlled by the inclination of the lamp signal.

FIG. 3 is a timing chart showing an operation example of the first imaging region 131-1 and the second imaging region 131-2. In this example, lamp signals having different inclinations are used for the first imaging region 131-1 and the second imaging region 131-2.

In FIG. 3, ADC1 input shows the waveform of the first image signal input to the first AD conversion unit 180-1, and Ramp1 shows the waveform of the first lamp signal generated by the first lamp generation unit 182-1. , ADC1 out indicates the magnitude of the digital value output by the first AD conversion unit 180-1 by the length on the time axis. Similarly, ADC2 input shows the waveform of the second image signal input to the second AD conversion unit 180-2, and Ramp2 shows the waveform of the second lamp signal generated by the second lamp generation unit 182-2. The ADC 2 out indicates the magnitude of the digital value output by the second AD conversion unit 180-2 by the length on the time axis.

In this example, the waveforms of the first image signal and the second image signal are the same for comparison. Further, the image sensor 100 of this example performs so-called correlated double sampling CDS. When an H level reset signal is input to the reset transistor 154, the charge accumulated in each photoelectric conversion unit 104 is reset, and the level of the image signal input to each AD conversion unit 180 becomes a predetermined reference level. ..

Each lamp generation unit 182 generates a lamp signal in a state where the level of the image signal is stable. In this example, the initial level of the lamp signal is larger than the reference level of the image signal, and the level decreases at a constant rate with time. The AD conversion unit 180 measures the period from the start timing of the level reduction of the lamp signal to the timing when the level of the lamp signal becomes smaller than the level of the image signal. As a result, the AD conversion unit 180 outputs a digital value indicating the reference level of the image signal.

Next, when the transfer signal Tx is input to the transfer transistor 152, an image signal corresponding to the amount of electric charge accumulated by the photoelectric conversion unit 104 is input to the AD conversion unit 180. The lamp generation unit 182 generates a lamp signal in a state where the level of the image signal is stable. The AD conversion unit 180 measures the period from the start timing of the level reduction of the lamp signal to the timing when the level of the lamp signal becomes smaller than the level of the image signal. As a result, the AD conversion unit 180 outputs a digital value indicating the level of the image signal. The luminance value of the pixel of the photoelectric conversion unit 104 is calculated from the difference between the level and the reference level.

As described above, in this example, lamp signals having different inclinations with respect to the first imaging region 131-1 and the second imaging region 131-2 are used. Therefore, as shown in FIG. 3, even if the waveforms of the image signals are the same, the values of the output digital image signals are different. For example, the larger the slope of the waveform of the lamp signal, the smaller the value of the digital image signal. In this way, by independently controlling the inclination of each lamp signal, it is possible to control the gain between the input and output in each AD conversion unit 180.

Each lamp generation unit 182 may generate lamp signals having different inclinations depending on the difference in sensitivity in the corresponding photoelectric conversion unit 104. Here, the sensitivity refers to the gain of the level of the image signal with respect to the intensity of the incident light. Sensitivity may also refer to the level gain of the image signal with respect to the intensity of a particular wavelength component of incident light.

FIG. 4 is a diagram showing an example of a plurality of imaging regions 131. In this example, the first imaging region 131-1 has a plurality of first photoelectric conversion units 104-1 and the second imaging region 131-2 has a plurality of second photoelectric conversion units 104-2. Although only two imaging regions 131 are shown in FIG. 4, the imaging unit 120 includes a larger number of imaging regions 131. Each photoelectric conversion unit 104 is included in any of the imaging regions 131. In addition, each transistor shown in FIG. 2 is provided in each photoelectric conversion unit 104.

The first photoelectric conversion unit 104-1 is a photoelectric conversion unit for focal detection that detects the focal position of the optical system through which the incident light has passed. However, the signal output by the first photoelectric conversion unit 104-1 is used not only for focus detection but also as an image signal constituting an image. The second photoelectric conversion unit 104-2 is a photoelectric conversion unit that is not for focus detection.

Generally, the sensitivity of the first photoelectric conversion unit 104-1 for focus detection is different from the sensitivity of the other second photoelectric conversion unit 104-2. For example, the first photoelectric conversion unit 104-1 has a light shielding unit 122 that shields half of the light receiving surface from light. That is, the sensitivity of the first photoelectric conversion unit 104-1 may be about half that of the other second photoelectric conversion unit 104-2. The first lamp generation unit 182-1 generates a lamp signal that compensates for the decrease in sensitivity. For example, the first lamp generation unit 182-1 generates a lamp signal having a slope that is half that of the second lamp signal. As a result, the gain in the first AD conversion unit 180-1 becomes twice the gain in the second AD conversion unit 180-2, and the difference in sensitivity between the first photoelectric conversion unit 104-1 and the second photoelectric conversion unit 104-2 is reduced. Can be compensated.

FIG. 5 is a diagram showing another example of the plurality of imaging regions 131. The imaging unit 120 of this example has three imaging regions 131. In FIG. 5, one or two photoelectric conversion units 104 included in each imaging region 131 are shown, and the configuration of the entire imaging region 131 is omitted. The first photoelectric conversion unit 104-1 included in the first image pickup region 131-1 converts the first wavelength component of the incident light into the first image signal. The second photoelectric conversion unit 104-2 included in the second image pickup region 131-2 converts the second wavelength component of the incident light, which is different from the first wavelength component, into the second image signal. The third photoelectric conversion unit 104-3 included in the third image pickup region 131-3 converts the third wavelength component different from the first wavelength component and the second wavelength component of the incident light into the third image signal. In this example, the first wavelength component is a component corresponding to green, the second wavelength component is a component corresponding to blue, and the third wavelength component is a component corresponding to red. Each photoelectric conversion unit 104 may have a color filter that allows a predetermined wavelength component to pass through.

Since each photoelectric conversion unit 104 converts incident light that has passed through a color filter or the like having different characteristics into an image signal, the sensitivities of the image signal to the incident light before passing through the color filter or the like do not always match. Each lamp generation unit 182 generates a lamp signal having a slope corresponding to the sensitivity of the corresponding photoelectric conversion unit 104. This makes it possible to compensate for the difference in sensitivity of each photoelectric conversion unit 104.

The lamp generation unit 182 may be provided in common for a plurality of imaging regions 131 having the same sensitivity. For example, the image pickup device 100 includes three lamp generation units 182 corresponding to each color of green, blue, and red, and each lamp generation unit 182 has one or more ADs corresponding to one or more image pickup areas 131 corresponding to each color. A lamp signal may be supplied to the conversion unit 180. Further, the image sensor 100 may further include a lamp generation unit 182 corresponding to the image pickup region 131 for focus detection shown in FIG.

FIG. 6 is a diagram showing another example of the plurality of imaging regions 131. The lamp generation unit 182 in this example controls the inclination of the lamp signal according to the position of the corresponding imaging region 131. For example, the lamp generation unit 182 may control the inclination of the lamp signal according to the distance from the center of the entire imaging region. By such control, even if the incident light amount varies depending on the position of the imaging region 131 due to the characteristics of the optical system, it is possible to compensate for the level difference of the image signal due to the variation. The slope of the lamp signal to be adopted for each imaging region 131 may be determined based on the level of the image signal output by each imaging region 131 when a known reference light is incident. ..

FIG. 7 is a diagram showing a configuration example of the imaging unit 120 and the plurality of AD conversion units 180. Although the lamp generation unit 182 is omitted in FIG. 7, the AD conversion unit 180 and the lamp generation unit 182 are provided one-to-one.

The image pickup unit 120 has a plurality of photoelectric conversion units 104 arranged in a matrix. The imaging unit 120 of this example has N photoelectric conversion units 104 in the column direction and M photoelectric conversion units 104 in the row direction. Further, in this example, P × M AD conversion units 180 are provided. Note that P is a divisor of N, and in the example of FIG. 7, P = 4.

In this example, each imaging region 131 includes N / P photoelectric conversion units 104. The AD conversion unit 180 and the imaging region 131 have a one-to-one correspondence. That is, each AD conversion unit 180 is provided corresponding to the N / P photoelectric conversion units 104, and sequentially reads out the image signals of the corresponding photoelectric conversion units 104. In this example, four AD conversion units 180 are provided in each row. Each AD conversion unit 180 is connected to photoelectric conversion units 104 arranged every four in the row.

For example, the first AD conversion unit 180-1 is connected to the 1, 5, 9, ..., N, n + 4, ..., N-3 th photoelectric conversion unit 104 in the column. Similarly, the second AD conversion unit 180-2 is connected to the second, 6, 10, ..., N + 1, n + 5, ..., N-2nd photoelectric conversion unit 104 in the column. The third AD conversion unit 180-3 is connected to the 3, 9, 11, ..., N + 2, n + 7, ..., N-1th photoelectric conversion unit 104 in the column, and the fourth AD conversion unit 180-4. Is connected to the 4, 8, 12, ..., N + 3, n + 7, ..., Nth photoelectric conversion unit 104 in the column.

In the example shown in FIG. 7, the plurality of AD conversion units 180 and the plurality of lamp generation units 182 are provided on the same surface as the plurality of photoelectric conversion units 104 in the image pickup unit 120. The P AD conversion units 180 provided in the same row may read the image signals at the same timing, and may also read the image signals at different timings.

FIG. 8 is a timing chart showing an operation example of four AD conversion units 180 provided in the same row. In this example, four image signals of the photoelectric conversion unit 104 in the same row are simultaneously read out. In FIG. 8, Selectx indicates the number of the photoelectric conversion unit 104 that inputs an image signal to the xth AD conversion unit 180.

The same reset signal Reset is input to each photoelectric conversion unit 104. The cycle of the reset signal Reset is, for example, 2 to 20 μs. Then, the transfer signal Tx at the same timing is input to the photoelectric conversion unit 104 of the n, n + 1, n + 2, and n + 3rd. Further, as the photoelectric conversion unit 104 to read out the image signal, the n, n + 1, n + 2, and n + 3rd photoelectric conversion unit 104 are simultaneously selected by the selection signal Select. Each AD conversion unit 180 simultaneously reads out the image signal of the selected photoelectric conversion unit 104.

Then, according to the next reset signal Reset, the image signals of the n + 4, n + 5, n + 6, and n + 7th photoelectric conversion units 104 are simultaneously read out in the same procedure. By such an operation, P (4 in the example of FIG. 8) image signals of the photoelectric conversion unit 104 are simultaneously read out every predetermined cycle (for example, 2 to 20 μs). Therefore, when the image signal of the photoelectric conversion unit 104 in each row is read out by the rolling method, the difference in the reading timing becomes the cycle of the reset signal Reset.

FIG. 9 is a timing chart showing details of the operations of the first AD conversion unit 180-1 and the second AD conversion unit 180-2 in the operation example shown in FIG. In this example, the slopes of the first lamp signal Ramp1 and the second lamp signal Ramp2 are different, as in the example shown in FIG. As described with reference to FIG. 3, the gains of the first AD conversion unit 180-1 and the second AD conversion unit 180-2 differ depending on the slope of the lamp signal. As described with reference to FIG. 8, the operation timings of the first AD conversion unit 180-1 and the second AD conversion unit 180-2 are the same.

FIG. 10 is a timing chart showing other operation examples of the four AD conversion units 180 provided in the same row. In this example, the read timings of the four AD conversion units 180 are shifted by ΔT. Specifically, the read timing of each AD conversion unit 180 is deviated by a value obtained by dividing the reset signal period (for example, 2 to 20 μs) by P. In this example, the read timing deviation ΔT is ΔT = 2 to 20 μs / 4 = 0.5 to 5 μs.

In this example, the phases of the reset signals input to the respective photoelectric conversion units 104 are shifted by ΔT. Further, the phases of the transfer signal Tx and the selection signal Select input to the respective photoelectric conversion units 104 are also shifted by ΔT. Further, the read timing of the AD conversion unit 180 is also shifted by ΔT.

FIG. 11 is a timing chart showing details of the operations of the first AD conversion unit 180-1 and the third AD conversion unit 180-3 in the operation example shown in FIG. In this example, the slopes of the first lamp signal Ramp1 and the third lamp signal Ramp3 are different, as in the example shown in FIG.

Further, in order to shift the read timing of the AD conversion unit 180 by ΔT, the timing at which each lamp generation unit 182 generates the lamp signal is also shifted by ΔT. That is, the timing of the first lamp signal Ramp1 and the third lamp signal Ramp3 are different by 2 × ΔT. The timing at which each lamp generation unit 182 generates a lamp signal is, for example, the timing at which the corresponding reset signal Reset is delayed by a predetermined delay amount.

As shown in FIGS. 10 and 11, by shifting the timing of the lamp signal, the difference in the reading timing when reading the image signal by the rolling method is 1 / as compared with the example shown in FIGS. 8 and 9. It can be multiplied by P. Therefore, it is possible to acquire an image with less distortion.

FIG. 12 is a diagram showing an image of a read timing difference in rolling read. The upper side of FIG. 12 shows the read timing difference in the examples shown in FIGS. 8 and 9, and the lower side shows the read timing difference in the examples shown in FIGS. 10 and 11.

In FIG. 12, the left end in the row direction indicates the read timing of the photoelectric conversion unit 104 in each row. That is, the step in the row direction indicates the timing difference. As described above, by shifting the timing of the lamp signal in the lamp generation unit 182, the read timing difference can be multiplied by 1 / P.

FIG. 13A is a diagram showing a configuration example of a plurality of lamp generation units 182. In this example, the image pickup device 100 has a seed lamp generation unit 190 and a plurality of lamp generation units 182a. The seed lamp generation unit 190 generates a seed lamp signal having a predetermined inclination. In this example, each lamp generation unit 182a has an amplifier that branches and receives the seed lamp signal, amplifies and outputs the seed lamp signal. The amplification factor in each lamp generation unit 182a can be controlled independently. As a result, each lamp generation unit 182a can generate a lamp signal having a slope according to the amplification factor.

Further, each lamp generation unit 182a may further have a variable delay element for delaying the seed lamp signal. As a result, each lamp generation unit 182a can independently control the timing of the lamp signal.

FIG. 13B is a diagram showing another configuration example of the plurality of lamp generation units 182. In this example, the image pickup device 100 has a clock generation unit 192, a plurality of lamp generation units 182b, and a lamp control unit 188. The clock generation unit 192 generates a clock signal having a predetermined frequency. In this example, each lamp generation unit 182b has a DA converter that outputs a digital signal given from the lamp control unit 188 at the frequency of the clock signal. The lamp control unit 188 sequentially inputs digital values whose values change with a predetermined inclination to the lamp generation unit 182b, and outputs a lamp signal.

The lamp control unit 188 can output lamp signals having different inclinations by independently controlling the inclination of the digital value for each lamp generation unit 182b. Further, the lamp control unit 188 can independently control the timing of inputting the digital value for each lamp generation unit 182b, so that the lamp signals having different start timings can be output.

FIG. 14 is a cross-sectional view of the image pickup device 100 according to the present embodiment. In this example, the so-called back-illuminated image sensor 100 is shown, but the image sensor 100 is not limited to the back-illuminated type and may be a front-illuminated type. The image pickup device 100 may have a structure including a laminated chip laminated on the image pickup chip 113.

The image pickup device 100 of this example includes an image pickup chip and 113 that output an image signal corresponding to incident light, a signal processing chip 111 that processes the image signal, and a memory chip 112 that stores the image signal. The image pickup chip 113, the signal processing chip 111, and the memory chip 112 are laminated and electrically connected to each other by a plurality of conductive bumps 109 such as Cu. In this example, the signal processing chip 111 and the memory chip 112 correspond to the above-mentioned laminated chips.

As shown in the figure, the incident light is mainly incident in the Z-axis plus direction indicated by the white arrow. In the present embodiment, in the image pickup chip 113, the surface on the side where the incident light is incident is referred to as a back surface. Further, as shown in the coordinate axes, the right direction of the paper surface orthogonal to the Z axis is defined as the X-axis plus direction, and the Z-axis and the front direction of the paper surface orthogonal to the X-axis are defined as the Y-axis plus direction.

An example of the image pickup chip 113 is a back-illuminated MOS image sensor. The image pickup chip 113 corresponds to the image pickup unit 120 shown in FIGS. 1 to 13B. The PD layer 106 is arranged on the back surface side of the wiring layer 108. The PD layer 106 has a plurality of photoelectric conversion units 104 that generate electric charges according to light. The image pickup chip 113 outputs an image signal corresponding to the electric charge. The PD layer 106 of this example has a plurality of photoelectric conversion units 104 arranged two-dimensionally, and a transistor 105 provided corresponding to the photoelectric conversion unit 104. The transistor 105 corresponds to each transistor in FIG. 2 and the like.

A color filter 102 is provided on the incident side of the incident light in the PD layer 106 via the passivation film 103. The color filter 102 has a plurality of types that transmit different wavelength regions from each other, and has a specific arrangement corresponding to each of the photoelectric conversion units 104. A set of a color filter 102, a photoelectric conversion unit 104, and a transistor 105 forms one pixel.

A microlens 101 is provided on the incident side of the incident light in the color filter 102 corresponding to each pixel. The microlens 101 collects incident light toward the corresponding photoelectric conversion unit 104.

The wiring layer 108 has a wiring 107 that transmits an image signal from the PD layer 106 to the signal processing chip 111. The wiring 107 may have multiple layers, and may be provided with passive elements and active elements.

A plurality of bumps 109 are arranged on the surface of the wiring layer 108. The plurality of bumps 109 are aligned with the plurality of bumps 109 provided on the facing surfaces of the signal processing chip 111, and the image pickup chip 113 and the signal processing chip 111 are aligned by being pressurized or the like. The bumps 109 are joined together and electrically connected.

Similarly, a plurality of bumps 109 are arranged on the surfaces of the signal processing chip 111 and the memory chip 112 facing each other. These bumps 109 are aligned with each other, and the signal processing chip 111 and the memory chip 112 are pressurized, so that the aligned bumps 109 are joined to each other and electrically connected.

The bonding between the bumps 109 is not limited to the Cu bump bonding by solid phase diffusion, but the micro bump bonding by solder melting may be adopted. Further, for example, one bump 109 may be provided for one output wiring described later, or a plurality of bumps 109 may be provided. The size of the bump 109 may be larger than the pitch of the photoelectric conversion unit 104. Further, in the peripheral region other than the pixel region in which the pixels are arranged, a bump larger than the bump 109 corresponding to the pixel region may be provided together.

The signal processing chip 111 receives an analog image signal output by the image pickup chip 113. The signal processing chip 111 performs predetermined signal processing on the received image signal and outputs the signal to the memory chip 112. The memory chip 112 stores a signal received from the signal processing chip 111.

The signal processing chip 111 of this example is provided with a plurality of AD conversion units 180 and a plurality of lamp generation units 182. The signal processing chip 111 may perform a predetermined operation such as correction on the digital image signal.

At least a part of the plurality of AD conversion units 180 is arranged two-dimensionally on the ADC arrangement surface parallel to the surface provided with the plurality of pixels. For example, in the image pickup chip 113, a plurality of pixels are arranged two-dimensionally along the row direction and the column direction, and in the signal processing chip 111, a plurality of AD conversion units 180 are arranged two-dimensionally along the row direction and the column direction. Will be done. It is preferable that the plurality of AD conversion units 180 are arranged at equal intervals in the signal processing chip 111. Further, the plurality of AD conversion units 180 may be non-uniformly arranged on the ADC arrangement surface of the signal processing chip 111. For example, the plurality of AD conversion units 180 may be arranged so that the end portion has a higher density than the center of the ADC arrangement surface of the signal processing chip 111.

Further, the plurality of AD conversion units 180 may be arranged on a plurality of ADC arrangement surfaces having different positions in the Z-axis direction in the signal processing chip 111. That is, the signal processing chip 111 is a multilayer chip, and the plurality of AD conversion units 180 may be provided in different layers. Also in this case, it is preferable that the AD conversion units 180 are arranged at equal intervals when the positions where the plurality of AD conversion units 180 are arranged are projected onto a single ADC arrangement surface.

Further, the signal processing chip 111 has a TSV (Through Silicon Via) 110 for connecting circuits provided on the front and back surfaces to each other. The TSV 110 is preferably provided in the peripheral region. Further, the TSV 110 may also be provided in the peripheral area of the image pickup chip 113 and the memory chip 112.

FIG. 15 is a block diagram showing a configuration example of the image pickup apparatus 500 according to the embodiment. The image pickup device 500 includes a photographing lens 520 as a photographing optical system, and the photographing lens 520 guides a subject light flux incident along the optical axis OA to the image pickup element 100. The photographing lens 520 may be an interchangeable lens that can be attached to and detached from the image pickup apparatus 500. The image pickup device 500 mainly includes an image pickup element 100, a system control unit 501, a drive unit 502, a photometric unit 503, a work memory 504, a recording unit 505, and a display unit 506.

The photographing lens 520 is composed of a plurality of optical lens groups, and forms a subject light flux from the scene in the vicinity of the focal plane thereof. In addition, in FIG. 15, it is represented by one virtual lens arranged in the vicinity of the pupil. The drive unit 502 is a control circuit that executes charge accumulation control such as timing control and area control of the image pickup unit 120 according to an instruction from the system control unit 501. In this example, the drive unit 502 and the system control unit 501 may have the functions of the AD conversion unit 180 described in relation to FIGS. 1 to 13B. As shown in FIG. 14, a part of the control circuit forming the drive unit 502 and the system control unit 501 may be chipped and stacked on the image pickup chip 113.

The image sensor 100 passes the image signal to the image processing unit 511 of the system control unit 501. The image pickup device 100 is the same as the image pickup device 100 described with reference to FIGS. 1 to 13B. The image processing unit 511 performs various image processing using the work memory 504 as a workspace to generate image data. For example, when generating image data in a JPEG file format, a compression process is executed after performing a white balance process, a gamma process, or the like. The generated image data is recorded in the recording unit 505, converted into a display signal, and displayed on the display unit 506 for a preset time.

The photometric unit 503 detects the luminance distribution of the scene prior to a series of shooting sequences that generate image data. The photometric unit 503 includes, for example, an AE sensor having about 1 million pixels. The calculation unit 512 of the system control unit 501 receives the output of the photometric unit 503 and calculates the brightness for each area of the scene. The calculation unit 512 determines the shutter speed, the aperture value, and the ISO sensitivity according to the calculated luminance distribution. The pixels used for the AE sensor may be provided in the image pickup unit 120, and in this case, the photometric unit 503 separate from the image pickup unit 120 may not be provided.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that the form with such changes or improvements may be included in the technical scope of the present invention.

The order of execution of each process such as operation, procedure, step, and step in the apparatus, system, program, and method shown in the claims, specification, and drawings is particularly "before" and "prior to". It should be noted that it can be realized in any order unless the output of the previous process is used in the subsequent process. Even if the scope of claims, the specification, and the operation flow in the drawings are explained using "first", "next", etc. for convenience, it means that it is essential to carry out in this order. It's not a thing.
[Item 1]
A plurality of pixels arranged in the row direction and the column direction intersecting the row direction, respectively.
A first signal conversion unit that converts the first signal into a digital signal based on a comparison result between the first signal output from the first pixel and the first lamp signal among the plurality of pixels.
Comparison of the second signal output from the second pixel arranged on the column direction side from the first pixel among the plurality of pixels and the second lamp signal having a gradient different from that of the first lamp signal. Based on the result, the second signal conversion unit that converts the second signal into a digital signal,
An image sensor comprising.
[Item 2]
In the image pickup device according to item 1,
The first lamp generation unit that generates the first lamp signal, and
The second lamp generation unit that generates the second lamp signal, and
An image sensor comprising.
[Item 3]
In the image pickup device according to item 1 or item 2,
A first signal line connected to the first pixel and outputting the first signal,
A second signal line connected to the second pixel and outputting the second signal,
An image sensor comprising.
[Item 4]
In the image pickup device according to item 3,
A plurality of the first pixels are arranged in the first region where light is incident.
A plurality of the second pixels are arranged in the second region where the light is incident.
The first signal line is connected to each of the first pixels arranged in a plurality in the first region.
The second signal line is an image pickup element connected to each of the second pixels arranged in a plurality in the second region.
[Item 5]
In the image pickup device according to item 4,
The first pixel is arranged side by side in the column direction and the row direction.
The second pixel is an image pickup element arranged side by side in the column direction and the row direction.
[Item 6]
In the image pickup device according to any one of items 1 to 5,
The first pixel and the second pixel are arranged on an image pickup chip having a first semiconductor substrate, and the first pixel and the second pixel are arranged on an image pickup chip.
The first signal conversion unit and the second signal conversion unit are image pickup devices arranged on a signal processing chip having a second semiconductor substrate.
[Item 7]
In the image pickup device according to item 6,
The image pickup chip is an image pickup element laminated by the signal processing chip.
[Item 8]
The image sensor according to any one of items 1 to 7 and the image sensor.
An image processing unit that performs image processing on the first signal converted into a digital signal by the image pickup element and the second signal converted into a digital signal by the image pickup element.
An image pickup device equipped with.

100 image pickup element, 101 microlens, 102 color filter, 103 passion film, 104 photoelectric converter, 105 transistor, 106 PD layer, 107 wiring, 108 wiring layer, 109 bump, 110 TSV, 111 signal processing chip, 112 memory chip, 113 image pickup chip, 120 image pickup section, 122 shading section, 131 image pickup area, 152 transfer transistor, 154 reset transistor, 156 amplification transistor, 158 selection transistor, 180 AD converter, 182 lamp generator, 184 level comparator, 186 period measurement 188 lamp control unit, 190 seed lamp generation unit, 500 image pickup device, 520 shooting lens, 501 system control unit, 502 drive unit, 503 photometric unit, 504 work memory, 505 recording unit, 506 display unit, 511 image processing unit 512 arithmetic unit

Claims (15)

The first photoelectric conversion unit that converts light into electric charge,
The second photoelectric conversion unit that converts light into electric charge,
A first lamp generation unit that generates a first lamp signal having the first characteristic,
A second lamp generation unit that generates a second lamp signal having a second characteristic,
The first signal is converted into a digital signal based on the comparison result between the first signal based on the charge converted by the first photoelectric conversion unit and the first lamp signal generated by the first lamp generation unit. 1st signal conversion unit and
The second signal is converted into a digital signal based on the comparison result between the second signal based on the electric charge converted by the second photoelectric conversion unit and the second lamp signal generated by the second lamp generation unit. With a second signal conversion unit
The first photoelectric conversion unit and the second photoelectric conversion unit are arranged in the same row on the first semiconductor chip.
The first lamp generation unit and the second lamp generation unit are image pickup devices arranged on a second semiconductor chip connected to the first semiconductor chip . In the image pickup device according to claim 1,
The first signal line from which the first signal is output and
A second signal line from which the second signal is output is provided.
The first signal conversion unit has a first comparator that compares the first signal output to the first signal line with the first lamp signal output from the first lamp generation unit.
The second signal conversion unit is an image pickup device having a second comparator that compares the second signal output to the second signal line with the second lamp signal output from the second lamp generation unit. .. In the image pickup device according to claim 2,
The first comparator is an image pickup device arranged on the second semiconductor chip. In the image pickup device according to claim 3,
The second comparator is an image pickup device arranged on the second semiconductor chip. In the image pickup device according to claim 2,
The first signal conversion unit is a first measurement unit that measures a period from when the input of the first lamp signal to the first comparator is started to when the comparison result of the first comparator is output. Have and
The second signal conversion unit is a second measurement unit that measures a period from when the input of the second lamp signal to the second comparator is started to when the comparison result of the second comparator is output. Have and
The first measuring unit is an image pickup device arranged on the second semiconductor chip. In the image pickup device according to claim 5,
The second measuring unit is an image pickup device arranged in the second semiconductor chip. The image pickup device according to any one of claims 1 to 6.
The first lamp signal has a first slope as the first characteristic.
The second lamp signal is an image pickup device having a second inclination as the second characteristic. The image pickup device according to any one of claims 1 to 6.
An image pickup device including a light-shielding unit that shields a part of the first photoelectric conversion unit from light-shielding. In the image pickup device according to claim 8,
The first lamp signal has a first slope as the first characteristic.
The second lamp signal has a second slope as the second characteristic.
The first tilt is an image sensor smaller than the second tilt. The image pickup device according to any one of claims 1 to 7.
The first photoelectric conversion unit converts the light from the filter having the first spectral characteristic into an electric charge.
The second photoelectric conversion unit is an image pickup device that converts light from a filter having a second spectral characteristic into electric charges. The image pickup device according to any one of claims 1 to 10.
A plurality of the first photoelectric conversion units are arranged in the first semiconductor chip, and the first photoelectric conversion unit is arranged.
The second photoelectric conversion unit is a plurality of image pickup devices arranged in the first semiconductor chip. In the image pickup device according to claim 11,
The first photoelectric conversion unit is arranged side by side in the row direction and the column direction.
The second photoelectric conversion unit is an image pickup device arranged side by side in the row direction and the column direction. The image pickup device according to any one of claims 1 to 12 .
The first semiconductor chip is an image pickup device laminated by the second semiconductor chip . The image pickup device according to any one of claims 1 to 13 .
An image processing unit that performs image processing on the first signal converted into a digital signal by the first signal conversion unit and the second signal converted into a digital signal by the second signal conversion unit .
An image pickup device equipped with. An image pickup unit having a plurality of image pickup areas and
A plurality of signal conversion units provided corresponding to the imaging region and converting an analog signal into a digital signal,
A plurality of lamp generation units provided corresponding to the signal conversion unit and generating lamp signals are provided.
The plurality of imaging regions include a first imaging region including a first photoelectric conversion unit that converts light into electric charges, and a second imaging region including a second photoelectric conversion unit that converts light into electric charges.
The plurality of lamp generation units include a first lamp generation unit that generates a first lamp signal having a first characteristic, and a second lamp generation unit that generates a second lamp signal having a second characteristic.
The plurality of signal conversion units are based on the comparison result between the first signal based on the charge converted by the first photoelectric conversion unit and the first lamp signal generated by the first lamp generation unit. The first signal conversion unit that converts the first signal into a digital signal, the second signal based on the charge converted by the second photoelectric conversion unit, and the second lamp signal generated by the second lamp generation unit. It has a second signal conversion unit that converts the second signal into a digital signal based on the comparison result of the above.
The first photoelectric conversion unit and the second photoelectric conversion unit are arranged in the same row on the first semiconductor chip.
The first lamp generation unit and the second lamp generation unit are image pickup devices arranged on a second semiconductor chip connected to the first semiconductor chip.

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